From: botp <botpena@...>
Date: 2010-05-31T20:21:16+09:00
Subject: Re: enumerator problem in 1.9.1

On Mon, May 31, 2010 at 4:34 PM, Robert Klemme
<shortcutter@googlemail.com> wrote:
> 2010/5/31 botp <botpena@gmail.com>:
>> On Mon, May 31, 2010 at 9:04 AM, Bug Free <amberarrow@yahoo.com> wrote:
>>> The following line:
>>>
>>>    [5, 7].each_with_index.each_cons(2) {|v| p v }
>>>
>>> prints [5, 7] but I'm expecting [[5, 0], [7, 1]].
>>
>> you'll have specify the index, eg,
>>
>>>>  [5, 7].map.with_index{|v,i| [v,i]}
>> => [[5, 0], [7, 1]]
>
> That's not the proper replacement with map.  Rather you'd do:
>
> irb(main):009:0> [5, 7].each_with_index.map {|v| v }
> => [5, 7]
> irb(main):010:0> [5, 7].each_with_index.map {|*v| v }
> => [[5, 0], [7, 1]]

brain dead here.
can you enlighten me on what is "not proper" ?  :)

ie why is each_with_index.map preferable over map.with_index ?

kind regards -botp